Inverter-integrated electrical compressors, which integrally incorporate inverter devices, are used as air conditioner compressors installed in electric vehicles, hybrid vehicles, and the like. This inverter-integrated electric compressor is configured so that high voltage direct current power supplied from a power supply unit installed in a vehicle is converted to three-phase alternating current power of a specified frequency, which is then applied to the electric motor so that the electric motor is driven.
An inverter device is constituted by, for example, high-voltage system components, such as inductor coils, smoothing capacitors, and the like provided on a high-voltage line from a power source, that reduce high-frequency noise, current ripples, and the like; a power system circuit board on which is mounted a switching circuit constituted by a plurality of switching elements (power elements), such as IGBT, that convert direct current power to three-phase alternating current power; a control system circuit board (printed circuit board) on which is mounted a control circuit that operates at a low voltage, such as a CPU; a busbar that interconnects these high-voltage system components, the power system circuit board, and the control system circuit board; and the like. The inverter device is configured so as to convert the direct current power that is input via a P-N terminal into three-phase alternating current power, which is then output from a UWV terminal.
A variety of assembly structures have been provided for the housing of this inverter device. Patent Document 1 discloses an inverter-integrated electric compressor in which a unit having a printed circuit board and a resin-insert-molded busbar assembly which also serves as an external frame integrated therein, the unit is fastened onto a seating face of a housing, on which a plurality of high-voltage components, such as switching elements, capacitors, and the like, are mounted, the terminals of the various electrical components are interconnected by the busbar, the interior of the external frame is filled with gel material and a cover plate is mounted thereto.
Additionally, Patent Document 2 discloses an inverter-integrated electric compressor in which an inverter housing section provided on the outer circumference of a housing has a high-voltage system component, such as a smoothing capacitor, and a coil, a metal power system circuit board, and a control system circuit board integrally formed therein via a resin case, an inverter module filled with gel material is assembled in the inverter housing section and is electrically connected via a busbar.
Furthermore, Patent Document 3 discloses an inverter-integrated electric compressor in which an inverter module having a metal power system circuit board and control system circuit board integrated therein is assembled into an inverter housing section of a housing, high-voltage system component and the like are sub-assembled using another housing case, and the subassembly is assembled into the housing and electrically connected via a busbar.